Mena Antibody #2075

Mena, EVL, and VASP are all members of the Ena/VASP family, which is involved in controlling cell shape and cell movement by shielding actin filaments from capping proteins (1). Ena/VASP proteins have three distinct domains: an amino-terminal EVH1 domain controlling protein localization; a central proline-rich domain mediating interactions with SH3 and WW domain containing proteins, including profilin; and a carboxy-terminal domain that promotes tetramerization and actin binding (2). Mena (known also as ENAH, or Protein enabled homolog), interacts with actin filaments at the growing ends and is thus localized to lamellipodia and the tips of neuronal growth cone filopodia. Axons projecting from interhemispheric cortico-cortical neurons were shown to be misrouted in newborn, homozygous Mena knockout mice (3). Mena may be phosphorylated at Ser236 by PKA, a posttranslational modification that is reported to promote filopodial formation and elongation of the growth cone (4). Three forms of the Mena protein, with apparent molecular weights of 80, 88 and 140 kDa, have been described. The 80 kDa isoform is broadly expressed, whereas the 140 kDa isoform is reportedly enriched in neural cell types; these isoforms are generated by alternative splicing. The 88 kDa isoform is expressed primarily in embryonic cells and is likely the result of posttranslational modification of the 80 kDa isoform. Expression of all three forms is completely eliminated after homozygous deletion of ENAH, the gene encoding the Mena protein (1,3).